- #1
amitSingh95
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1. Homework Statement
The system is in equilibrium. All the surfaces in the image are rough. The direction of friction on B due to A is :
(a) is upward
(b) is downward
(c) is zero
(d) depends on the masses of A and B.
ANS : (a)
Homework Equations
MAg = 2μN (Friction due to wall and due to B)
N=F
The Attempt at a Solution
Since the gravitational force is balanced by the frictional force on A by B and the wall, the direction of frictional force due to B and the wall on A must be upward and therefore, direction of force due to A on B must be downward, i.e., (b), but I am not sure that my reasoning is correct and I don't understand why it should be upward?